I have one of these now, which had failed caps under the HDD caddy.
All of the 2200uf, 1800uf, 1500uf, 820uf and small 220uf caps have been done bar a couple of tiny 100uf or less caps and the odd 120uf Sanyo caps.

If I plug the machine in for the first time, the internal orange light flashes on, then goes out - like it has detected a short. It won't power on.
Unplugging the PSU and trying it again, it works fine and the machine operates normally.

2 different PSUs tried, which work fine on an SX280.

Tested with the board removed from the tray with all items removed (CPU, RAM etc), same symptoms.

Yes. - On 620's I think it was. [Some older Dell based thread anyway.]
Area near the drive is a low air flow hot spot.
Even the small caps go bad there.
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Also happens sometimes when the small caps are 85C.
.

__________________Mann-Made Global Warming.- We should be more concerned about the Intellectual Climate.
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Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.- Dr Seuss-You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
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The 745 USFF's have a small fan under there too....doesn't seem to help, I see boxes and boxes full of these boards, all with bad MCZ and/or KZJ's. Dell stopped using the 85* nichicon's (I think they were VR series, but don't hold me to that) around the NB chip (220@16v were the values), and finally went with 105*, usually rubycons or pannies. Havent seen one bad since.

Yes. - On 620's I think it was. [Some older Dell based thread anyway.]
Area near the drive is a low air flow hot spot.
Even the small caps go bad there.
.
Also happens sometimes when the small caps are 85C.
.

Done those now, same issue

No 85˚c caps on this, all 105˚c.
I guess I should stick Windows on it and see what happens, it'll soon BSOD if it's not well.

Connect PSU brief 'flash' of orange standby light.
Disconnect and re-connect PSU - orange standby light lit and the machine will do it's self test and power on fine.

The 745 USFF's have a small fan under there too....doesn't seem to help, I see boxes and boxes full of these boards, all with bad MCZ and/or KZJ's. Dell stopped using the 85* nichicon's (I think they were VR series, but don't hold me to that) around the NB chip (220@16v were the values), and finally went with 105*, usually rubycons or pannies. Havent seen one bad since.

Usually Nichicon VR. - Sometimes they were more creative.

They've been bouncing back and forth between 85C and 105C for the small caps at least since P-III.
You can have two otherwise identical boards but one has the 85C and the other 105C.
.
Maybe they've finally figured it out but I wouldn't be surprised at all to see 85C showing up again.

...
Intel has gone China on us.
Some of their newer non-server boards are showing up with Lelon all over.
.
Pic is a DH55HC board which only has a few. [H55 chipset]
Been seeing Lelons on Intel boards from the H55 at least back to the 31 series chipsets.
I don't mean OEM boards either. Talking retail models.
Some boards have LOTS of them.
.

I had a 745 come in a couple weeks ago, with four bad 2200uf/6.3v caps near the northbridge. That's not particularly unusual in and of itself, except that this particular machine was a tower. All the other 745s I'd worked on had been SFF machines, but apparently the larger ones aren't safe either.

Where I work we have 120 OptiPlex GX620 machines (mercifully almost all have been ok for 5 years), but of the 10 or so OptiPlex 745 workstations, 5 have now died with bad caps on the motherboard. The symptoms were hard lockups showing a full screen of the same colour (e.g. orange, white, green, grey). We use onboard gfx. Three failed in warranty, and now another two. Dell are refusing to support them as they're not on their list of bad cap machines. They were bought in May 2007, so they would be inside a discretionary 5 year warranty as mentioned here:http://en.community.dell.com/dell-bl...tor-issue.aspx

On some of the failed machines all the caps near the gfx card slot are domed, on others just two of them. When the service guy came to swap motherboards on the ones that were repaired he said he had seen hundreds. Conveniently Dell "have no records" of my previous Support Requests being capacitor-related, even though obviously those third party service contractors must write up the cases.

I had a 745 come in a couple weeks ago, with four bad 2200uf/6.3v caps near the northbridge. That's not particularly unusual in and of itself, except that this particular machine was a tower. All the other 745s I'd worked on had been SFF machines, but apparently the larger ones aren't safe either.

I've got 10 or 12 full-size 745s still in service, they've all bee rock-solid.
Ok, one bad video card.... but motheboards and power supplies have been fine.

Where I work we have 120 OptiPlex GX620 machines (mercifully almost all have been ok for 5 years), but of the 10 or so OptiPlex 745 workstations, 5 have now died with bad caps on the motherboard. The symptoms were hard lockups showing a full screen of the same colour (e.g. orange, white, green, grey). We use onboard gfx. Three failed in warranty, and now another two. Dell are refusing to support them as they're not on their list of bad cap machines. They were bought in May 2007, so they would be inside a discretionary 5 year warranty as mentioned here:http://en.community.dell.com/dell-bl...tor-issue.aspx

On some of the failed machines all the caps near the gfx card slot are domed, on others just two of them. When the service guy came to swap motherboards on the ones that were repaired he said he had seen hundreds. Conveniently Dell "have no records" of my previous Support Requests being capacitor-related, even though obviously those third party service contractors must write up the cases.

That warranty extension was specifically to cover a run of defective Nichicon HM and HN series caps.
That was over with before GX620 went into production.
[The defective caps were flushed out of the supply channels by Nichicon World Wide in 2004.]
The GX280 was still in production.
Early production GX280 were the last (Dell) machines affected.
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What you probably have is the common heat issue with the Dell small case machines.
Those cases don't have adequate cooling. - They never have.
.

It's 2015 and I still find 745 mini tower's with bad caps. My local goodwill is packed full of 745's. They sale them as part machines for like $6 to $12 each. The power supply's rev0, 1 & 2 tend have failed caps 3,4 & 5 seem ok.

I've also come across a 740 (AMD) and a precision 690 workstation (Xeon) with bad caps.

I have a Dell Dimension 2400, still cranking. No bad caps, and what's more amazing, that computer used to be running in a company 24/7 for I guess since the computer went into service. It was a miracle it made it out of the company chain. Mainly, when business computers get put out of service, they get the D-Day treatment, get dumped, put in storage to be forgotten, or (VERY RARELY) get wiped and get sold to Goodwill. Even more rarely is that the computer is given directly to a computer user. The thing that happened here was the computer was taken out of service and taken home by I believe a company worker. That computer got lucky.

__________________
Don't buy those $10 PSU "specials". They fail, and they have taken whole computers with them.

i had a 755 that randomly didnt want to turn on. i pressed a little on a few caps and it worked fine for a few weeks.

then i remembered when i worked at dell in 2006/7 that there was a bad batch of first rev boards "due to manuf process" for first 2 or 3 months. then they got recalled or something. but im not sure if it was the 745 or 755.

anyways i ended up using the 220uF 10v caps for 95-98 honda accord DX AT ECU from the dell 755 ( had to do it emergency for car and couldnt find local cap seller or tv shop willing to sell me some) .. i gave up on it not thinking it was caps due to "manuf process issue"